THIS IS A SHANNON AWARD PROVIDING PARTIAL SUPPORT FOR THE RESEARCH PROJECTS THAT FALL SHORT OF THE ASSIGNED INSTITUTE'S FUNDING RANGE BUT ARE IN THE MARGIN OF EXCELLENCE. THE SHANNON AWARD IS INTENDED TO PROVIDE SUPPORT TO TEST THE FEASIBILITY OF THE APPROACH; DEVELOP FURTHER TESTS AND REFINE RESEARCH TECHNIQUES; PERFORM SECONDARY ANALYSIS OR AVAILABLE DATA SETS; OR CONDUCT DISCRETE PROJECTS THAT CAN DEMONSTRATE THE PI'S RESEARCH CAPABILITIES OR LEND ADDITIONAL WEIGHT TO AN ALREADY MERITORIOUS APPLICATION. THE ABSTRACT BELOW IS TAKEN FROM THE ORIGINAL DOCUMENT SUBMITTED BY THE PRINCIPAL INVESTIGATOR. DESCRIPTION (Adapted from the Applicant's Abstract): The factors responsible for progression of skeletal deformities, especially in growing children, are poorly understood. This makes it difficult to treat these deformities. The goal of this research is to develop a predictive model of the progression of angular skeletal deformities in growing children for use in the planning of treatment. Progressive deformities in growth cartilages are commonly thought to be controlled by the `Hueter-Volkmann Law', which states that growth is retarded by increased mechanical compression, and accelerated by reduced loading of the growth plate in comparison with normal values. The predictive model will include, as inputs, the present shape of the deformity and the amount of residual growth. This work is intended to provide new insights into the mechanics of progression of deformity, and permit quantitative design of mechanical treatment by techniques such as bracing, muscle stimulation and surgery. The emphasis of this work is on spinal deformity. Three parallel sets of studies directed at quantifying the rate of endochondral growth of vertebrae, and the growth of intervertebral discs as a function of mechanical environment and the effects on progressive deformity are proposed. For the first approach (animal model), a previously developed rat tail model, which has documented altered growth in tail vertebrae subjected to forces applied via an external ring fixator, will be used to quantify this effect, and to determine the mechanisms responsible for it. Also, the model will be extended from a simple axial load paradigm, to a model of asymmetric loading and asymmetric growth in a wedge-deformity, and shear forces. Growth and development of the intervertebral discs also will be documented. For approach #2, biomechanical analyses of the forces in the muscles and the degree of asymmetric loading of a spine with lateral curvature (scoliosis) will be made. These analyses will be combined with knowledge of growth sensitivity to load from the rat tail experiments, in order to develop the predictive model of scoliosis progression. The third investigative arm represents clinical studies. Radiographs of patients with progressive deformity will be measured in a longitudinal study to plot the development of the deformity in terms of vertebral body and intervertebral disc wedging. Surprisingly, very little is known about how the lateral curvature in scoliosis is distributed between deformity of the vertebrae and discs. These measurements will be used to test the accuracy of the predictive model.